Anno Domini
Western calendar era
Anno Domini (AD) and before Christ (BC) qualify years in the Gregorian and Julian calendars, whose epoch is the traditional year of the conception or birth of Jesus. AD counts years since the epoch, BC the years before the epoch.
Anno Domini is Medieval Latin for "in the year of the Lord", often read as "our Lord". "BC" is specific to English, and equivalent abbreviations are used in other languages: the Latin form, rarely used in English, is ante Christum natum (ACN) or ante Christum (AC).
This calendar era takes as its epoch the traditionally reckoned year of the conception or birth of Jesus. Years AD are counted forward since that epoch and years BC are counted backward from the epoch. There is no year zero; the year AD 1 immediately follows the year 1 BC. The system was devised in 525, in Rome, by the Eastern Roman monk Dionysius Exiguus, but was not widely used until the 9th century. Modern scholars believe that the actual date of the birth of Jesus was about 5 BC.
To avoid religious associations, many writers and scholars prefer CE (Common Era) and BCE (Before the Common Era) instead of AD and BC.
Astronomical year numbering and ISO 8601 do not use words or abbreviations related to Christianity, but use the same numbers for AD years (but not for BC years since the astronomical year 0 is 1 BC).
Usage
Traditionally, English follows Latin usage by placing the "AD" abbreviation before the year number, though it is also found after the year. In contrast, "BC" is always placed after the year number (for example: 70 BC but AD 70), which preserves syntactic order.
“Anno Domini” enters the record as western calendar era. Crown Archives preserves that source wording while asking what Anno, Domini and Western can confirm, complicate or overturn.
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“Anno Domini” is worth following because a concise public description often conceals a longer documentary argument. Here, Anno, Domini and Western provides the most credible route into that argument.
The citation trail is more important than the brevity of the summary: it shows where individual claims can be examined in context. The source revision retrieved here is dated Sep 22, 2026. The linked authority identifier is Q159791. None of the 0 selected statements returned an explicit reference.
The absence of detail may reflect summary conventions rather than a lack of surviving documentation. The lead is largely declarative, so disagreement and counter-evidence require a deliberate search beyond the opening account. Authority statements aid reconciliation but still require their own references, qualifiers and ranks to be checked.
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This entry incorporates text from “Anno Domini” on English Wikipedia. Contributors are listed in the page history. Text is available under the Creative Commons Attribution-ShareAlike 4.0 License. Selected authority identifiers and statements are retrieved from Wikidata under CC0; their references and qualifiers remain part of the verification path.